1. Field of the Invention
The present invention relates to an image forming apparatus, a method for controlling the image forming apparatus, and a storage medium.
2. Description of the Related Art
In an image forming apparatus including a central processing unit (CPU) on each of a main board and a sub-board, device control and image processing, which require real time processing, are performed on the sub-board side. Devices such as a printer, a scanner, and a facsimile are controlled on the sub-board side. In a case where an operational failure occurs in software on the sub-board side during control of a device, the device cannot be controlled at desired timing.
When a device in operation cannot be controlled, the device needs to be stopped immediately. To stop the device, a function of a watchdog timer installed on the sub-board side is used. The watchdog timer is regularly cleared within a certain time period defined by the software. However, in case of the software failure, this clear operation cannot be performed. When a predetermined time period has elapsed, the hardware is reset. The resetting of the hardware resets a device control module, thereby stopping the operation of the device.
Japanese Patent Application Laid-Open No. 4-33138 discusses a technique applied to a multi-CPU system including a main board and a sub-board. According to the technique, when it is detected that the CPU on the sub-board side is out-of-control, the sub-board side is automatically rebooted.
However, when the sub-board side is reset using a watchdog timer, the main board side cannot recognize the presence of the sub-board side, thereby resulting in an error. Such a software failure on the sub-board side cannot be predicted by the main board side, and also the main board side cannot receive a prior notification from the sub-board side. Consequently, the main board side cannot execute appropriate processing.